近红外光调制下金刚石 NV 色心自旋动力学与电荷态转化研究

对金刚石氮-空位(nitrogen-vacancy, NV)色心电子自旋态进行光学操控的过程中, 近红外光是一种重要手段, 对色心自旋态和电荷态布居能产生显著影响, 定量研究近红外光对NV色心自旋动力学的作用具有重要意义。文章用实验测量室温下532 nm激光连续激发单个NV色心产生的荧光时间曲线, 并建立七能级模型进行数值模拟, 得到各自旋能级间跃迁速率; 在此基础上用1 040 nm激光对色心荧光时间曲线进行调制, 实验数据与数值模拟结果相吻合。研究结果表明, 近红外光对金刚石NV色心自旋态的影响主要体现在对电荷态转化速率的提高上, 使用功率为40 mW的1 040 nm激光和532 nm激光一起照射, 可以将电离速率和复合速率分别提升约15倍和30倍。

Near-infrared(NIR) light is an important method in the optical manipulation of spin states in nitrogen-vacancy(NV) center in diamond, which has a significant influence on the spin and charge state population. Therefore, it is of great significance to quantitatively study the effect of NIR light on the spin dynamics of NV center. In this paper, the time-resolved fluorescence of a single NV center under continuous 532 nm laser was measured experimentally at room temperature. The transition rates between energy levels were obtained through numerical simulation by establishing a seven-level model. On this basis, 1 040 nm laser was used to modulate the time-resolved fluorescence of NV center, and the experimental data were in good agreement with the numerical simulation. The results show that the influence of NIR light on the NV center spin dynamics mainly lies in the improvement of charge state conversion rate. The ionization rate and recombination rate can be increased by about 15 and 30 times respectively via irradiation of 1 040 nm laser with 40 mW power and 532 nm laser together.